As if fans haven’t heard enough recently about labor strife in sports, now comes word that the National Basketball Referee’s Association is accusing the NBA of engaging in unfair labor practices.

As reported by Yahoo! Sports, the referees’ union has filed charges to the National Labor Relations Board, claiming the league, in violation of federal laws, has refused to negotiate on several non-economic issues. The filing also says that a league negotiator -- identified by sources as commissioner David Stern -- directed an “obscene expression” at union negotiators during a Jan. 24 meeting.

NBA referees are unhappy with the league over several non-economic issues. (AP photo)

The non-economic issues on which the union claims the league refuses to negotiate include those related to weight and fitness restrictions, travel issues and anti-discrimination based on race, sex and union activity, according to Yahoo! The document filed with the NLRB contends that the union, during the Jan. 24 meeting, sought to include what it believes is “standard language” on discrimination found in many collective bargaining agreements. When it did, the document said, “one of the league’s negotiators reacted to it with hostility and resorted to the use of an obscene expression in describing its effect. When the NBRA representatives declined his demand to delete the obscene expression from their notes, this negotiator abruptly left the room.”

News of Stern’s reaction follows another recent report that said the commissioner used a questionable analogy when addressing NBA All-Stars in Los Angeles in February, telling the players he knows “where the bodies are buried” around the league.

“The NLRB will ultimately decide whether the NBA has violated federal law,” Lee Seham, a labor attorney representing the refs, said in an email to Yahoo! “Our view is that the NBA’s current refusal to negotiate over such issues as discrimination, or the league’s ability to terminate a referee without cause, is an act of bad faith. The NBRA hopes the league will perceive a mutual interest in ensuring the integrity of basketball. In our view, telling the referees that they can be fired without cause defeats that objective.”

The NBA declined comment.

The league’s CBA with the referees expires Sept. 1. Its labor deal with the players ends on June 30.